Five-year Analysis of a Multi-institutional Prospective Clinical Trial of Delayed Intervention and Surveillance for Small Renal Masses: The DISSRM Registry

BackgroundA growing body of retrospective literature is emerging regarding active surveillance (AS) for patients with small renal masses (SRMs). There are limited prospective data evaluating the effectiveness of AS compared to primary intervention (PI).ObjectiveTo determine the characteristics and clinical outcomes of patients who chose AS for management of their SRM.Design, setting, and participantsFrom 2009 to 2014, the multi-institutional Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) registry prospectively enrolled 497 patients with solid renal masses ≤4.0 cm who chose PI or AS.InterventionAS versus PI.Outcome measurements and statistical analysisThe registry was designed and powered as a noninferiority study based on historic recurrence rates for PI. Analyses were performed in an intention-to-treat manner. Primary outcomes were overall survival (OS) and cancer-specific survival (CSS).Results and limitationsOf the 497 patients enrolled, 274 (55%) chose PI and 223 (45%) chose AS, of whom 21 (9%) crossed over to delayed intervention. AS patients were older, had worse Eastern Cooperative Oncology Group scores, total comorbidities, and cardiovascular comorbidities, had smaller tumors, and more often had multiple and bilateral lesions. OS for PI and AS was 98% and 96% at 2 yr, and 92% and 75% at 5 yr, respectively (log rank, p = 0.06). At 5 yr, CSS was 99% and 100% for PI and AS, respectively (p = 0.3). AS was not predictive of OS or CSS in regression modeling with relatively short follow-up.ConclusionsIn a well-selected cohort with up to 5 yr of prospective follow-up, AS was not inferior to PI.Patient summaryThe current report is among the first prospective analyses of patients electing for active surveillance of a small renal mass. Discussion of active surveillance should become part of the standard discussion for management of small renal masses.